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Building Technologies Basic documentation LMV37.4... CC1P7546en
HVAC Products 6 Basic unit 01.12.2009
6.3.9 Pressure switch-max-gas (Pmax) / or POC contact / max-oil,
start release oil X5–02
Input for connection of a pressure switch-max for gas or oil: The pressure switch must
have an NC contact, which means that the contact opens when the adjusted maximum
pressure is exceeded. If the plant does not require a pressure switch-max, a wire link
must be fitted between terminal 2 and terminal 3.
Caution!
The OEM must check to see whether the burner can be operated without using
a pressure switch-max. This may necessitate a special approval, depending on
the application.
LMV...
Bild 279e/0409
X5-02
Pmax/POC
Protective earth PE
Pressure switch-max or POC
L for pressure switch
Figure 14: Pressure s witch-max-gas (Pmax) / -max-oil or POC X5-02
The connection can also be used as POC (Proof of Closure) (refer to Sequence dia-
gram).
No. Parameter
237
Gas: Pressure switch-max / POC input
0 = deactivated
1 = Pressure switch-max
2 = POC
&
Note
If the input is used for POC, pressure switch-max can be included in the safety loop.
In that case, pressure switch-max must not be fitted between the valves, but after
them.
Pressure switch-max-gas
In all types of gas trains, the maximum gas pressure is monitored from phase 40. If the
maximum gas pressure is exceeded, the system initiates lockout.
Error
code
Diagnostic
code
Meaning for the LMV37.4... system
14 0 POC open
1 POC closed
21 0 Pressure switch-max (Pmax): Max. gas pressure ex-
ceeded
POC: POC open (software version ≤V02.00)
1 POC closed (software version ≤V02.00)
During the safety times (TSA1 / TSA2), the signal from pressure switch-max is only as-
sessed after a certain period time has elapsed in order to ignore the pressure shocks
that occur the moment the valves open.
No. Parameter
229
Gas: Time to respond to pressure faults within safety time 1 (TSA1) and safety
time 2 (TSA2)
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